Spacer device

ABSTRACT

A spacer unit inlet member integrally constructed of rigid or non-flexible material and capable of selectively mounting about its opening any one of a plurality of metered dose inhaler (MDI) actuators having different outlet size or shape. The inlet member includes a channel providing an opening of the inlet member and being formed by a wall substantially parallel to its rotational axis A peripheral edge of the wall is shaped substantially as a truncated oval. The inlet member further includes a pair of opposing curved walls surrounding and substantially parallel to the rotational axis of the channel and having an outermost edge comprising a substantially oval shape, and a wall substantially perpendicular to the rotational axis of the channel and positioned between the walls of the channel and the opposing curved walls.

This Application is a National Phase under 35 U.S.C. §371 ofInternational Application PCT/AU02/00332, filed Mar. 21, 2002designating the US and published in English as WO 02/074371, whichclaims the benefit of priority of Australian Provisional Application No.PR 3877, filed Mar. 21, 2001, both of which are incorporated herein byreference in their entireties.

FIELD OF THE INVENTION

The present invention relates generally to the field of medical devicesfor the inhalation of medicaments that comprise dry powder, liquid, orgas, and, more particularly to improvements to conventional spacer unitsdesigned for use with a metered dose inhaler (MDI), said improvementproviding for the attachment of said spacer to a plurality of MDIshaving differently shaped actuators.

All patents, patent applications, and publications cited herein areincorporated by reference in their entirety.

As used herein the words “from” or “of”, and the term “derived from”shall be taken to indicate that a specified integer may be obtained froma particular source albeit not necessarily directly from that source.

As used herein, the term “substantially” shall be taken to mean that astated integer approximates a stated characteristic, without a strictadherence to any mathematical formula or geometric consideration. Forexample, the term “substantially parallel” means that a stated integerapproximates the parallel position or extends in the same direction asan integer with respect to which the reference is made, without beingnecessarily precisely parallel. Similarly, the term “substantiallyperpendicular” shall be taken to mean that a stated integer approximatesthe perpendicular position or extends in the transverse direction to aninteger with respect to which the reference is made, without beingnecessarily precisely perpendicular.

Throughout this specification, unless the context requires otherwise,the word “comprise”, or variations such as “comprises” or “comprising”,will be understood to imply the inclusion of a stated step or element orinteger or group of steps or elements or integers but not the exclusionof any other step or element or integer or group of elements orintegers.

Those skilled in the art will appreciate that the invention describedherein is susceptible to variations and modifications other than thosespecifically described It is to be understood that the inventionincludes all such variations and modifications. The invention alsoincludes all of the steps, features, compositions and compounds referredto or indicated in this specification, individually or collectively, andany and all combinations or any two or more of said steps, features,compositions and compounds.

The present invention is not to be limited in scope by the specificembodiments described herein, which are intended for the purposes ofexemplification only. Functionally equivalent products, compositions andmethods are clearly within the scope of the invention, as describedherein.

BACKGROUND TO THE INVENTION

Inhalable medicaments, such as, for example, those for the prophylacticor therapeutic treatment of asthma or bronchitis, are commonlyadministered to patients using a metered dose inhaler (MDI). An MDIgenerally comprises a container housing the medicament, an axiallyextending vent tube from an internal valve, and a hollow actuator unitthat houses the container and feeds the medicament to the patient viaits outlet portion. The medicament is commonly packed in the containerwith a suitable propellant, such as, for example, a substance capable offorming a liquid under pressure and entering the gas phase at lowpressure.

In use, the patient brings the outlet of the actuator to his/her mouth,depresses the container relative to the actuator, thereby activating theinternal valve to dispense a measured dose of medicament into thepatient's mouth. In this arrangement, it is often necessary for thepatient to coordinate his/her inhalation with the depression of thecontainer to ensure that a sufficient dose of the medicament enters thepatient's airway. The medicament will generally include a liquid/gasmixture of propellant, wherein small drops of medicament/propellantmixture enter the patient's airway with the medicament and rapidlyprojected particles of medicament/propellant mixture are deposited inthe throat and mouth and are swallowed. Accordingly, the need tocoordinate the dispensing of medicament with the patient's inhalation,and the dispensing of medicament/propellant mixture from the MDI, reducethe efficiency of treatment. Moreover, there is a need to allow thedeceleration and dispersal of particles to minimize deposition in thethroat and mouth.

To enhance the efficacy of treatment, a spacer is commonly attached tothe outlet of the actuator. Alternatively, the actuator is removed andthe spacer is attached directly to the container via the vent tube. Aspacer is a simple expansion chamber conveniently in the form of a smallcylinder, conical or pear-shaped, into which a medicament that isdispensed from an MDI can be held prior to inhalation by a patient.

In use, one end of a spacer is attached to the outlet of the MDI, andthe other end of the spacer is received into the patient's mouth. Asealing engagement between the spacer and the MDI is required tominimize drug/medicament leakage, thereby ensuring that an adequate doseof medicament is received by the spacer unit. The patient depresses thecontainer of the MDI relative to the actuator, thereby activating theinternal valve to dispense a measured dose of medicament into thespacer. In a separate action to dispensing of the medicament from theMDI, the patient inhales air/medicament/propellant mixture from thespacer into his/her airway. Accordingly, the spacer provides anadvantage in so far as there is no need for the patient to coordinatehis/her inhalation with the depression of the container of the MDI.Additionally, the spacer facilitates the deceleration and dispersal ofparticles of the medicament into smaller particles, for efficientinhalation.

As will be known to those skilled in the art, a rigid material, such as,for example, polycarbonate, is preferred for construction of a spacer.This is because such a rigid material confers strength and durability onthe device. Additionally, polycarbonate is heat-resistant, facilitatingsteam sterilization and washing of the device in a dishwasher.

Standard spacers are constructed with at least two separate pieces: (i)a hollow inlet member having an opening for attaching an MDI actuator tofacilitate the flow of medicament from the MDI to the spacer unit, (ii)a hollow outlet member having an opening for attaching a mouthpiece ormask to facilitate delivery of the medicament to the patient, and often(iii) a separate barrel-shaped element between elements (i) and (ii).During assembly, the components are snap-locked; or screwed together insealing engagement to form an interior space for holding the medicamentduring use, and two openings to facilitate the flow of a medicamentthrough the assembled unit.

Spacer devices are described in detail by Nowacki et al. in U.S. Pat.No. 4,470,412; and by InfaMed Limited in international Application No.PCT/AU99/00290.

Notwithstanding the advantages of using a spacer, such devices doincrease the costs associated with treatment relative to the cost of theMDI alone. Moreover, as drug companies generally provide their MDI withan actuator having an outlet of a particular shape, not all actuatoroutlets are capable of being in sealing engagement with all spacerunits. Accordingly, it is highly desirable for a spacer unit to beuniversally adaptable to all MDI devices.

One solution to this problem is to provide an “adaptor” or “back piece”that attaches to the end of the spacer and is capable of attaching to aplurality of actuator outlets. For example, the adaptor described inU.S. Pat. No. 5,848,588 (Trudell Medical International) comprisesresilient, flexible material such as a rubber or the like, whereinconcentric cylinders cover and grip the end of a cylindrical spacer, anda transverse membrane extends inwardly therefrom and is provided with acentral opening, and straight and inwardly-directed ribs for receivingand gripping the outlet of the MDI. Pairs of the ribs have crossbracing, to control stretching of the diaphragm so that it provides aproper seal with an inserted MDI, whilst the radial inner ends of theribs provide support for the MDI.

Spacer devices that do not require a separate adaptor have been designedto fit most known MDI units, with varying success. Generally, theprovision of a universally-adaptable spacer of rigid construction hasbeen avoided because such a device would have been prone to breakingand/or cracking, during fitting to MDI outlets of different shapes.

Occasionally, rigid spacer devices have been designed with prong-shapedprotrusions to maximize flexure of the spacer to accommodate an MDIactuator. These protrusions are inherently brittle when made of a rigidplastic and are adaptable to very few types of actuators.

Accordingly, known spacers that are usable with a plurality of MDIdevices generally require prior removal of the MDI container from themanufacturer's actuator, and subsequent fitting of the container to thespacer unit. Poor sealing between the vent tube of the MDI and thespacer may result during such procedures.

Alternatively, it is known to fit the spacer with a flexible inlet toaccommodate various shaped MDI actuators. In fact, most conventionalspacers that fit a plurality of different MDI actuators provide aflexible adaptor end that stretches or is compressed relative to theactuator. However, such an arrangement cannot be easily produced as anintegral unit, because the spacer is generally made from rigid material,such as, for example, polycarbonate. This is a considerable disadvantagein terms of production of the device, because of the additional costsassociated with producing separate pieces. Additionally, by providing aspacer in multiple pieces, with an additional rubber-like adaptor endpiece, assembly of the device is made more complex, and requiresadditional effort either by the production team or the end user.

SUMMARY OF THE INVENTION

In work leading up to the present invention, the inventors sought toproduce a cost-effective spacer unit that is capable of fitting aplurality of differently shaped MDI devices without the need for priorremoval of the MDI canister from the actuator. The inventors realizedthat this object of the invention could be achieved by providing aspacer comprising a rigid material, such as that used in the manufactureof a conventional spacer device. To facilitate a reduction in productioncosts and time, the inventors produced such a spacer unit in as few astwo separate pieces, each of said pieces being of an integralconstruction that could be produced, for example, from a singleinjection mold or by blow molding.

Accordingly, one aspect of the present invention provides a spacer unitinlet member integrally constructed of rigid or non-flexible material,said member capable of selectively mounting about its opening any one ofa plurality of metered dose inhaler (MDI) actuators having differentoutlet size or shape, and comprising:

-   (i) a channel having a wall substantially parallel to its rotational    axis and surrounding or substantially coaxial to the opening of said    inlet member, wherein the peripheral edge of said channel is shaped    substantially as a truncated oval having a major axis and having a    pair of curved sides and a pair of opposite ends directed chordally    of said oval and substantially perpendicular to the major axis of    said oval;-   (ii) a pair of opposing curved walls surrounding and substantially    parallel to the rotational axis of said channel, and having an    outermost edge comprising a substantially oval shape; and-   (iii) a wall substantially perpendicular to the rotational axis of    said channel and positioned between said walls of said channel and    said opposing curved walls.

In use, one or more of the external faces of said channel is/are capableof contacting the inner or outer wall of the outlet of an MDI actuator.Alternatively, or in addition, one or more of said opposing curved wallsis/are capable of contacting the outer wall of the outlet of an MDIactuator. Alternatively, or in addition, the wall that is perpendicularto the rotational axis of the channel is also capable of contacting theperipheral edge of the outlet of an MDI actuator. The number andposition of the contacts between the spacer inlet member and the MDIactuator outlet will depend upon the size and shape of the MDI actuatoroutlet, however al sealing engagement is formed between one or morefaces of the MDI actuator outlet and one or more of said walls (i) or(ii) or (iii), to prevent the leakage of a medicament.

A second aspect of the present invention provides a spacer unitcomprising:

-   (i) an inlet member integrally constructed of rigid or non-flexible    material, said member capable of selectively mounting about its    opening any one of a plurality of metered dose inhaler (MDI)    actuators having different outlet size or shape, and including:    -   (a) a channel having a wall substantially parallel to its        rotational axis and surrounding or substantially coaxial to the        opening of said inlet member, wherein the peripheral edge of        said channel is shaped substantially as a truncated oval having        a major axis and having a pair of curved sides and a pair of        opposite ends directed chordally of said oval and substantially        perpendicular to the major axis of said oval;    -   (b) a pair of opposing curved walls surrounding and        substantially parallel to the rotational axis of said channel,        and having an outermost edge comprising a substantially oval        shape; and    -   (c) a wall substantially perpendicular to the rotational axis of        said channel and positioned between said walls of said channel        and said opposing curved walls, and-   (ii) a spacer unit outlet member is provided, and    wherein said inlet member and said outlet member are locked together    in sealing engagement to form an interior space for holding a    medicament during use, and two openings to facilitate the flow of a    medicament through the assembled unit.

The invention will best be understood from the following description ofpreferred embodiments when taken in connection with the accompanyingnon-limiting drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a spacer inlet member having one edge(10) for engaging a spacer outlet member (not shown) and an opposingopening (11) for attaching an MDI actuator (not shown) and through whicha medicament is released into the assembled spacer device during use.The spacer inlet member is a hollow member having a rotational axisindicated by the broken line. Surrounding opening (11) is a channel (16)having a plurality of walls substantially parallel to the rotationalaxis of the inlet member, and a peripheral edge (15) shapedsubstantially as a truncated oval. The channel is surrounded by opposingcurved walls (20 and 21) substantially parallel to the rotational axisof the channel, and having an outermost edge (23) substantially oval inshape with a major axis that is parallel to the major axis of theperipheral edge of the channel. The external face of the spacer inletmember has two opposing non-slip panels (stippled). Contour lines arealso shown.

FIG. 2 is a lateral view of the spacer inlet member of FIG. 1 showingthe edge (10) for engaging a spacer outlet member (not shown) and anopposing opening (11) for attaching an MDI actuator (not shown) andthrough which a medicament is released into the assembled spacer deviceduring use. The position of the channel (16) is indicated, relative tothe surrounding curved walls (20 and 21) that are contiguous with theexternal face of the spacer inlet member. The spacer inlet member has arotational axis indicated by the broken line. Contour lines are alsoshown.

FIG. 3 is a top view of the spacer device of FIG. 1, with the portion ofthe end at which the MDI actuator is attached removed to reveal theholding faces and sealing faces of the spacer inlet member that attachthe outlet of the MDI actuator during use. In particular, walls (36 and37) of channel (16), and walls (20 and 21) form holding faces toposition the outlet of the MDI actuator over the opening that surroundschannel (16). The peripheral; edge of the actuator forms a sealingengagement with the face (25) that consists in a surface between walls(36 and 37) and walls (20 and 21), said sealing face being substantiallyperpendicular to the rotational axis of channel (16). The edge (10) forengaging the spacer outlet member is also indicated. Broken lineindicates the rotational axis of the channel Hatching indicates thecontiguous external wall of the end portion of the spacer inlet member.

FIG. 4 is an end view of the spacer inlet member showing the relativepositions of the opening (11), channel (16) and surrounding opposingwalls (20 and 21). The external faces (35, 36, 37, and 38) of channel(16), and the internal faces of the opposing walls (20 and 21) areholding faces for positioning the outlet of the MDI actuator in place. Athird face, indicated by the cross hatched area (integer 25 in FIG. 3),contacts the peripheral edge of the MDI actuator outlet.

FIG. 5 is a perspective view of an assembled spacer unit comprising thespacer inlet member (5) as shown in FIGS. 1 to 4 in sealing engagementwith a spacer outlet member (6) at outer edge (10) of said inlet member,and having a breath-activated incentive whistle (12) and a breathactivated spinning orb (14) positioned between a mask (45) and spaceroutlet member (6) via a three way conduit (40). The positions of thechannel (16) and surrounding opposing walls (20 and 21) of the spacerinlet member are also indicated. The rotational axis of the spacer unitis indicated by the broken line.

FIG. 6 is a perspective view showing the assembled spacer device of FIG.5, with an MDI partially attached. The MDI comprises a canister orcontainer (55) with medicament stored inside and an actuator (50).During assembly, the outlet of the actuator (50) is positioned aroundthe channel (16), between the external walls of said channel and thesurrounding opposing walls (20 and 21). For complete assembly, somestretching or compression of the actuator outlet may be required, beforethe actuator outlet is positioned with its peripheral edge in sealingengagement with the sealing face (not shown).

FIG. 7 is a sectional view of two halves (hatched areas) of an open andshut dye used to manufacture the spacer inlet member of FIG. 1 as anintegral unit. The shaded line indicates the region of the dye to beoccupied by the walls of the spacer inlet member during casting. Singleunbroken lines indicate split lines separating the dye halves. Thearrows indicate the direction of dye draw to separate the dye halvesfollowing casting.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The term “spacer unit inlet member” includes that portion of a spacerunit that receives a medicament from an MDI or other drug deliverdevice. Similarly, the term “spacer unit outlet member” includes thatportion of a spacer unit from which a medicament is directly orindirectly dispensed to a patient. It is preferable to construct aspacer device in separate portions, to facilitate cleaning of the deviceto remove excess medicament, either before changing the medicament to beadministered, or in any event at regular intervals.

The spacer inlet member according to preferred embodiments of theinvention may be constructed of any rigid or non-flexible material usedto construct a standard spacer device. The terms “rigid” and “nonflexible” includes having a flexibility less than a plastic that isnormally used to construct an MDI actuator, and/or having a tensilestrength greater than that of said plastic, including any non-rubberizedmaterial.

In this respect, the preferred embodiments of the present invention arepredicated in part on the inventors' discovery that a range of differentsized and different shaped MDI outlets can be stretched over a rigidspacer channel without leading to cracking or breaking of the spacer.

Preferred rigid or non-flexible materials for use in constructing thespacer inlet member of the present invention include polycarbonate, TPA,polypropylene, and polyvinylchloride. Mixed polymers, such as, forexample, those comprising acrylonitrile, butadiene, and styrene (ABSpolymer), are also contemplated. However, the use of polycarbonate isparticularly preferred, because it is the material of choice forproducing spacer devices, due to its clarity, strength, durability, andheat resistance properties.

The selective mounting feature of preferred embodiments of the presentinvention is provided by a specific modification to the opening end of astandard spacer inlet member. By “selective mounting” it is meant thatany one of a number of different MDIs, such as, for example, the MDIsprovided by Glaxo Smith Kline (e.g. Ventahaler™ MDI), 3M Corporation(e.g. the Autohaler™ MDI), AstraZeneca, or Rhône Poulenc Rorer (e.g.Azmacort™ MDI or Intal™ MDI), can be separately positioned in sealingengagement with the spacer inlet member, around its opening.

By “sealing engagement” is meant that two or more integers are insufficient physical relation to prevent a degree of leakage ofmedicament that would compromise a dosage delivery to a patient. Personsskilled in the art will be aware of the leakage to be tolerated from anMDI without compromising its efficacy. Preferably, any such leakage isminimum and less than about 25% of the total dosage ejected from theMDI, more preferably less than about 5–10% of the total dosage.

As will be known to those skilled in the art, the term “opening” withreference to a spacer inlet member refers to that opening into whichmedicament is dispensed from an MDI during use. Those skilled in the artwill also be aware that the opening of the spacer inlet member may bepositioned anywhere on the surface of said inlet member, such as, forexample, at an end opposing that end which engages the spacer outletmember, or alternatively, on any side surface of the spacer inletmember, without adversely affecting: the function of the assembledspacer unit.

Furthermore, preferred embodiments of the present invention are notlimited by the overall size or shape of the spacer inlet member, theonly requirement being that it is compatible with a spacer outlet memberto which it is attached in use. For example, spacers of cylindricalshape, conical shape or pear shape are well known in the art, and thepresent invention encompasses spacer inlet members that are used forsuch spacers. Accordingly, the present invention is not to be limited tothe frustoconical appearance of the spacer inlet member depicted in theaccompanying drawings.

The surface of the spacer inlet member that interfaces with the MDIactuator outlet may be modified as desired. Persons skilled in the artwill readily be capable of adapting the representation of the surface ofthe spacer inlet member that interfaces with an MDI actuator outlet, asdepicted herein, to a variety of different shaped and sized spacer inletmembers.

In this respect, it is known for conventional spacer devices to includea channel, such as, for example, a female or male fitting, surroundingthe opening, or coaxial to the opening, wherein the MDI actuator outletis generally attached in sealing engagement with said channel.Conventional channels will generally have one or more wallssubstantially parallel to the rotational axis of the channel, to directthe flow of medicament to the inside of the assembled spacer device.

In the present arrangement, the peripheral edge of the channel is shapedsubstantially as a truncated oval having a major axis and having a pairof curved sides and a pair of opposite ends directed chordally of saidoval and substantially perpendicular to the major axis of said oval, tofacilitate contact with a number of differently shaped MDI actuatoroutlets, either throughout its entire length, or at specific contactpoints.

For example, the MDI actuator outlet may perfectly match the: shape ofthe channel, and forms a sealing engagement with the complete internalface or complete external face of said channel.

Alternatively, the MDI actuator may not match the shape of the channel,or be too large to form a sealing engagement with the external face ofthe channel, in which case the MDI actuator outlet will either contactthe channel at specific points along its external face, or not at all,and no sealing engagement will be formed that involves only the MDIactuator outlet and the channel. In such circumstances, the preferredembodiments of the present invention provide opposing walls that arecurved and surround the channel, to hold the MDI in place. In thisarrangement, one or more external faces of the channel and one or moreinternal faces of the surrounding opposing walls assist in holding, oractually hold, the actuator in place.

For example, the external face of the MDI actuator outlet may contactthe surrounding opposing walls throughout its length, and form a sealingengagement therewith.

Alternatively, if the MDI actuator outlet does not match the shape ofthe surrounding opposing curved walls precisely, then the MDI maycontact one or both of said walls at specific contact points.

Where such incomplete contact with the entire surface of the opposingcurved walls does occur, the position of the MDI may be stabilized byfurther points of contact with a part of the external face of thechannel, such as, for example, at the external face of one or more endwalls of the channel, or at one or more corners of the channel, or atthe external face of one or more of the curved walls of the channel.

It will be apparent from the preceding description that the nature ofthe contact between the MDI actuator outlet and the spacer inlet memberwill vary considerably between different MDI. The MDI actuator outletcan contact the spacer inlet member at one or more points, such as:

-   (i) the external face of the channel,-   (ii) the internal face of the curved walls surrounding the channel;-   (iii) the external walls running substantially perpendicular to the    major axis of the peripheral edge of the channel, and four points on    the internal face of the surrounding curved walls;-   (iv) the external walls running substantially perpendicular to the    major axis of the peripheral edge of the channel and the internal    portions of the internal faces of the two opposing curved walls; and-   (v) the external faces of the curved walls of the channel and one or    more points on the internal faces of the surrounding opposing curved    walls.

Where the above points of contact solus do not form a sealing engagementbetween the MDI actuator outlet and the spacer inlet member, then thereis provided a third wall in the spacer inlet member of the invention,positioned between the channel and the opposing walls and substantiallyperpendicular thereto, that is capable of forming a sealing engagementwith the peripheral edge of the actuator outlet, to prevent the leakageof medicament.

In use, the MDI actuator outlet may be compressed to fit within theouter opposing curved walls, or alternatively, stretched over thechannel to form a sealing engagement with the spacer inlet member.

Accordingly, it will be apparent from the preceding description that thespacer inlet member performs both a holding and a sealing function.

Preferably, the spacer inlet member is provided with one or moreinternal one-way valves, filters or baffles, to permit the passage ofmedication in one direction only, generally within the opening. Such anarrangement is described in detail in International Application No.PCT/AU99/00290, which is incorporated herein by way of reference.

In a particularly preferred embodiment of the invention, the spacerinlet member has a configuration substantially as set forth in FIGS. 1to 6. It is to be understood however, that the specific configurationset forth in the accompanying drawings is for the purposes ofexemplification only, and should not be taken as imposing any limitationon the invention.

A spacer inlet member is depicted in FIGS. 1 and 2. The spacer inletmember comprises an integral, frustoconical body portion, having arotational axis indicated by the broken line, and preferably constructedof clear polycarbonate. The body is hollow and open at both ends, andincludes an opening or inlet end 11 shown at the left of FIGS. 1 and 2,and a second end 10, shown at the right of FIGS. 1 and 2, for forming asealing engagement with a compatible spacer outlet member (not shown).The spacer inlet member is provided with grips on the external lateralsurface to prevent or reduce slipping, and to assist the user to gripthe assembled spacer unit. Surrounding opening (11) is a channel (16)having a plurality of walls substantially parallel to the rotationalaxis of the inlet member (broken line in FIGS. 1 and 2), and aperipheral edge (15) shaped substantially as a truncated oval. Theperipheral edge 15 of channel 16 forms an edge of the spacer inletmember in the exemplified embodiment. However, it is possible toconstruct a spacer inlet member wherein the opening 11 is separated fromthe channel 16 and coaxial therewith, in which case the periphery of thespacer inlet member will form an opening that is not at the periphery ofthe channel. In use, medicament enters the spacer inlet member throughopening 11. Surrounding channel 16 are two opposing curved walls 20 and21, joined at their ends such that their outermost edge 23 forms anapproximately oval shape. Edge 23 has a major axis that is parallel tothe major axis of the peripheral edge of the channel in, the exemplifiedembodiment, however the present invention also encompasses alternativearrangements wherein these axes are perpendicular to each other. Theopposing curved walls 20 and 21 that surround channel 16 areapproximately parallel to the rotational axis of the spacer inlet member(broken line in FIGS. 1 and 2), and approximately parallel to the wallsof channel 16. As shown in FIG. 2, it is not necessary for the walls 20and 21 to be planar members. However, for most applications, the centralportions of walls 20 and 21 are sufficiently prominent to be capable offorming a surface that contacts an MDI actuator outlet.

The surfaces of the spacer inlet member that interface with the MDIactuator outlet are shown in greater detail in FIGS. 3 and 4. FIG. 3shows two external faces 36 and 37, on the ends of channel 16 that areperpendicular to the major axis of its peripheral edge. Externalsurfaces 36 and 37, as well as other external surfaces of channel 16(e.g. surfaces 38 and 39 of FIG. 4), form holding surfaces that cancontact the MDI actuator outlet in use. The internal surfaces of walls20 and 21, that also form holding surfaces, are also shown in FIG. 3. Afurther wall 25 that is between and perpendicular to curved walls 20 and21 and external walls 36 and 37, forms a third possible surface forcontacting the MDI actuator outlet, as shown in FIGS. 3 and 4.

In use, and wherein the MDI actuator outlet has a shape substantiallythe same as that of the channel shown in FIG. 4, and is slightly largerin size than channel 16, the MDI actuator outlet will contact externalfaces 35, 36, 37, and 38 (FIG. 4) of channel 16, optionally extendingthroughout the length of channel 16 to also contact internal face 25,thereby forming a seal sufficient to minimize leakage of any dispensedmedicament from said MDI. Some stretching of the MDI actuator outlet maybe required to fit over the channel 16.

Alternatively, if the MDI actuator outlet has a rectangular or squareshape, the MDI actuator outlet will contact external faces 35 and 36 ofchannel 16, and; four points on the internal face of the surroundingcurved walls 20 and 21, optionally extending throughout the length ofchannel 16 to also contact internal face 25, thereby forming a sealsufficient to minimize leakage of any dispensed medicament from saidMDI. Some compression or stretching of the MDI actuator outlet may berequired to fit over the channel 16 and within the walls 20 and 21.

Alternatively, if the MDI actuator outlet has a shape that is the sameas channel 16, but has different dimensions to channel 16, the MDIactuator outlet will contact external faces 35 and 36 of channel 16, andthe central portions of the internal faces of walls 20 and 21,optionally extending throughout the length of channel 16 to also contactinternal face 25, thereby forming a seal sufficient to minimize leakageof any dispensed medicament from said MDI. Some compression orstretching of the MDI actuator outlet may be required to fit over thechannel 16 and within the walls 20 and 21.

Alternatively, wherein the MDI actuator has a shape substantially thesame as the outer edge 23 (FIG. 1), the MDI actuator outlet will contactinternal surfaces of walls 20 and 21 (FIG. 4), optionally extendingthroughout the length of walls 20 and 21 to also contact internal face25, thereby forming a seal sufficient to minimize leakage of anydispensed medicament from said MDI. Some compression of the MDI actuatoroutlet may be required to fit within walls 20 and 21.

Alternatively, if the MDI actuator outlet is cylindrical or conical(i.e. having an approximately circular outer edge) it will contact thespacer inlet member at the four corners between external surfaces 35,36, 37, and 38 of channel 16, and at an approximately central positionof the inner surfaces of walls 20 and 21, optionally extendingthroughout the length of walls 20 and 21 to also contact internal face25, thereby forming a seal sufficient to minimize leakage of anydispensed medicament from said MDI. Some compression of the MDI actuatoroutlet may to fit within walls 20 and 21, and/or stretching to fit overchannel 16 may be required.

Preferably, the inlet member and the outlet member are snap-lockedtogether, or alternatively, there are complementary threaded portionsprovided at the edges of the inlet and outlet members for screwing theparts together.

The spacer outlet member may be any conventional spacer outlet member,such as, for example, that described in International Application No.PCT/AU99/00290 or U.S. Pat. No. 4,470,412, amongst others. Preferably,the spacer outlet member is provided with one or more one way valves,filters or baffles, to confer a unidirectional flow of air andmedicament from the assembled spacer device to the patient. Such a valvearrangement may be placed, for example, near the opening of the outletmember, and may include ducts to allow exhaled air/medicament mixture tobe vented from the system into the surrounding atmosphere duringexhalation. Such an arrangement is described in detail in internationalApplication No. PCT/AU99/00290, which is incorporated herein by way ofreference.

Preferably, the spacer unit includes a three way conduit or separatorelement to facilitate the attachment of one or more incentive toy unitssuch as those described in International Application No. PCT/AU99/00290,to encourage infant users to use the spacer device, and teach a correctmode of breathing. According to this embodiment, the arrangementdescribed in International Application No. PCT/AU99/00290 causes theinhaled medicament to be functionally separated from the toy unitsduring the inhalation phase of breathing, to prevent the contaminationof said toy units with medicament during use, thereby reducing thenumber of parts in need of regular cleaning.

A particularly preferred embodiment of the spacer device of theinvention is shown in FIG. 5, wherein the spacer inlet member 5 is insealing engagement with spacer outlet member 6, about edge 10 of thespacer inlet member. The positions of channel 16 and curved walls 20 and21 of the spacer inlet member 5 are indicated, as is the rotational axisof the assembled spacer unit (broken line). A separator element, shownin FIG. 5 as a three way conduit 40, is attached at one end to theopening of spacer outlet member 6, at one end to a face mask 45, and atthe other end to two toy units in series. The toy units are representedas a spinning orb 14 and a whistle 12. The facemask 45 could be readilysubstituted with a mouthpiece without compromising function. Wherein theassembled spacer unit has internal one way valves, these may bepositioned within the spacer inlet member 5 and/or spacer outlet member6, preferably near their openings. Alternatively, or in addition, suchvalves may be positioned at any end of the three way conduit 45 tofacilitate the unidirectional flow of air or medicament over or throughthe toy units and/or through the assembled spacer device.

The MDI attaches to the assembled spacer device essentially as shown inFIG. 6, with the MDI actuator outlet 50 contacting the channel 16 andsliding between said channel and the surrounding curved walls 20 and 21.In use, medicament is released into the spacer device by depressing thecanister 55 of the MDI relative to the actuator outlet 50.

An additional advantage of the spacer inlet member is that it can beproduced inexpensively as an integral unit. For example, a singleinjection mold, such as using an ‘open-and-shut’ die that requires nosliding cores, and no undercuts, can be used to produce the inletmember. An example of such a die arrangement is shown in FIG. 7, whereinthe body of the spacer inlet member is stamped or extruded between twodye halves, and then the dye halves are drawn apart, leaving the formedmember as a hollow unit. In an alternative preferred embodiment, theinvention can be produced by means of blow molding, a process known tothose skilled in the art. Blow molding has the additional advantage ofbeing less costly than other procedures for producing the improvedspacer device of the invention.

1. A spacer unit inlet member integrally constructed of rigid ornon-flexible material, said member capable of selectively mounting aboutits opening a metered dose inhaler (MDI) actuator having an outlet ofgiven size or shape, and comprising: (i) a channel providing an openingof said inlet member, said channel being formed by a wall substantiallyparallel to a rotational axis of said channel, wherein a peripheral edgeof said wall is shaped substantially as a truncated oval having a pairof opposing curved sides and a pair of opposing chordal endssubstantially perpendicular to a major axis of said peripheral edge,(ii) a pair of opposing curved walls substantially parallel to therotational axis of said channel, and having an outermost edge comprisinga substantially oval shape, and (iii) a wall substantially perpendicularto the rotational axis of said channel and positioned between said wallof said channel and said opposing curved walls.
 2. The spacer unit inletmember according to claim 1, wherein one or more of external faces ofsaid channel is/are capable of contacting an inner or outer wall of theoutlet of the MDI actuator.
 3. The spacer unit inlet member according toclaim 1, wherein one or more of said opposing curved walls is/arecapable of contacting an outer wall of the outlet of the MDI actuator.4. The spacer unit inlet member according to claim 1, wherein the wallthat is perpendicular to the rotational axis of the channel is alsocapable of contacting the peripheral edge of the outlet of the MDIactuator.
 5. The spacer unit inlet member according to claim 1, whereina sealing engagement is formed between one or more faces of the MDIactuator outlet and one or more of said walls (i) or (ii) or (iii), toprevent a leakage of a medicament.
 6. A spacer unit comprising: (i) aninlet member integrally constructed of rigid or non-flexible material,said member capable of selectively mounting about its opening a metereddose inhaler (MDI) actuator having an outlet of given size or shape, andcomprising: (a) a channel providing an opening of said inlet member,said channel being formed by a wall substantially parallel to arotational axis of said channel wherein a peripheral edge of said wallis shaped substantially as a truncated oval having a pair of opposingcurved sides and a pair of opposing chordal ends substantiallyperpendicular to a major axis of said peripheral edge; (b) a pair ofopposing curved walls surrounding and substantially parallel to therotational axis of said channel, and having an outermost edge comprisinga substantially oval shape; and (c) a wall substantially perpendicularto the rotational axis of said channel and positioned between said wallof said channel and said opposing curved walls, and (ii) a spacer unitoutlet member, and wherein said inlet member and said outlet member arelocked together in sealing engagement to form an interior space forholding a medicament during use, and two openings to facilitate a flowof a medicament through the spacer unit.
 7. The spacer unit according toclaim 6, wherein the inlet member and the outlet member are snap-lockedtogether.
 8. The spacer unit according to claim 6, further comprisingcomplimentary threaded portions provided at the edges of the inlet andoutlet members for screwing the inlet and outlet members together. 9.The spacer unit according to claim 6, wherein the spacer outlet memberfurther comprises one or more one way valves, filters or baffles, toconfer a unidirectional flow of air and medicament from the spacer unitto a patient.
 10. The spacer unit according to claim 6, wherein thespacer outlet member is integrally constructed of rigid or non-flexiblematerial.
 11. The spacer unit according claim 6, wherein the spacer unitfurther comprises a three way conduit or separator element to facilitatean attachment of one or more incentive toy units.